DESCRIPTION

The Access Logging overlay can be used to record all accesses to a given backend database on another database. This allows all of the activity on a given database to be reviewed using arbitrary LDAP queries, instead of just logging to local flat text files. Configuration options are available for selecting a subset of operation types to log, and to automatically prune older log records from the logging database. Log records are stored with audit schema (see below) to assure their readability whether viewed as LDIF or in raw form.

CONFIGURATION

These slapd.conf options apply to the Access Logging overlay. They should appear after the overlay directive.

EXAMPLES

        database bdb
        suffix dc=example,dc=com
        ...
        overlay accesslog
        logdb cn=log
        logops writes reads
        logbase search|compare ou=testing,dc=example,dc=com
        logold (objectclass=person)

        database bdb
        suffix cn=log
        ...
        index reqStart eq
        access to *
          by dn.base="cn=admin,dc=example,dc=com" read

SCHEMA

The accesslog overlay utilizes the "audit" schema described herein. This schema is specifically designed for accesslog auditing and is not intended to be used otherwise. It is also noted that the schema described here is a work in progress, and hence subject to change without notice. The schema is loaded automatically by the overlay.

The schema includes a number of object classes and associated attribute types as described below.

There is a basic auditObject class from which two additional classes, auditReadObject and auditWriteObject are derived. Object classes for each type of LDAP operation are further derived from these classes. This object class hierarchy is designed to allow flexible yet efficient searches of the log based on either a specific operation type's class, or on more general classifications. The definition of the auditObject class is as follows:

Note that all of the OIDs used in the logging schema currently reside under the OpenLDAP Experimental branch. It is anticipated that they will migrate to a Standard branch in the future.

An overview of the attributes follows: reqStart and reqEnd provide the start and end time of the operation, respectively. They use generalizedTime syntax. The reqStart attribute is also used as the RDN for each log entry.

The reqType attribute is a simple string containing the type of operation being logged, e.g. add, delete, search, etc. For extended operations, the type also includes the OID of the extended operation, e.g. extended(1.1.1.1)

The reqSession attribute is an implementation-specific identifier that is common to all the operations associated with the same LDAP session. Currently this is slapd's internal connection ID, stored in decimal.

The reqDN attribute is the distinguishedName of the target of the operation. E.g., for a Bind request, this is the Bind DN. For an Add request, this is the DN of the entry being added. For a Search request, this is the base DN of the search.

The reqAuthzID attribute is the distinguishedName of the user that performed the operation. This will usually be the same name as was established at the start of a session by a Bind request (if any) but may be altered in various circumstances.

The reqControls and reqRespControls attributes carry any controls sent by the client on the request and returned by the server in the response, respectively. The attribute values are just uninterpreted octet strings.

The reqResult attribute is the numeric LDAP result code of the operation, indicating either success or a particular LDAP error code. An error code may be accompanied by a text error message which will be recorded in the reqMessage attribute.

The reqReferral attribute carries any referrals that were returned with the result of the request.

Operation-specific classes are defined with additional attributes to carry all of the relevant parameters associated with the operation:

For the Abandon operation the reqId attribute contains the message ID of the request that was abandoned.

The Add class inherits from the auditWriteObject class. The Add and Modify classes are very similar. The reqMod attribute carries all of the attributes of the original entry being added. (Or in the case of a Modify operation, all of the modifications being performed.) The values are formatted as

Where '+' indicates an Add of a value, '−' for Delete, '=' for Replace, and '#' for Increment. In an Add operation, all of the reqMod values will have the '+' designator.

The Bind class includes the reqVersion attribute which contains the LDAP protocol version specified in the Bind as well as the reqMethod attribute which contains the Bind Method used in the Bind. This will be the string SIMPLE for LDAP Simple Binds or SASL(<mech>) for SASL Binds. Note that unless configured as a global overlay, only Simple Binds using DNs that reside in the current database will be logged.

For the Compare operation the reqAssertion attribute carries the Attribute Value Assertion used in the compare request.

The Delete operation needs no further parameters. However, the reqOld attribute may optionally be used to record the contents of the entry prior to its deletion. The values are formatted as

The reqOld attribute is only populated if the entry being deleted matches the configured logold filter.

The Modify operation contains a description of modifications in the reqMod attribute, which was already described above in the Add operation. It may optionally contain the previous contents of any modified attributes in the reqOld attribute, using the same format as described above for the Delete operation. The reqOld attribute is only populated if the entry being modified matches the configured logold filter.

The ModRDN class uses the reqNewRDN attribute to carry the new RDN of the request. The reqDeleteOldRDN attribute is a Boolean value showing TRUE if the old RDN was deleted from the entry, or FALSE if the old RDN was preserved. The reqNewSuperior attribute carries the DN of the new parent entry if the request specified the new parent. The reqOld attribute is only populated if the entry being modified matches the configured logold filter and contains attributes in the logoldattr list.

For the Search class the reqScope attribute contains the scope of the original search request, using the values specified for the LDAP URL format. I.e. base, one, sub, or subord. The reqDerefAliases attribute is one of never, finding, searching, or always, denoting how aliases will be processed during the search. The reqAttrsOnly attribute is a Boolean value showing TRUE if only attribute names were requested, or FALSE if attributes and their values were requested. The reqFilter attribute carries the filter used in the search request. The reqAttr attribute lists the requested attributes if specific attributes were requested. The reqEntries attribute is the integer count of how many entries were returned by this search request. The reqSizeLimit and reqTimeLimit attributes indicate what limits were requested on the search operation.

The Extended class represents an LDAP Extended Operation. As noted above, the actual OID of the operation is included in the reqType attribute of the parent class. If any optional data was provided with the request, it will be contained in the reqData attribute as an uninterpreted octet string.

NOTES

The Access Log implemented by this overlay may be used for a variety of other tasks, e.g. as a ChangeLog for a replication mechanism, as well as for security/audit logging purposes.

FILES

SEE ALSO

slapd.conf(5), slapd-config(5).

ACKNOWLEDGEMENTS

This module was written in 2005 by Howard Chu of Symas Corporation.